Credit cards have gained widespread use in recent years and have come to be generally regarded as a third type of currency. Credit cards are widely used in place of cash and checks probably because people don't like to carry large amounts of cash and personal checks are not widely accepted, especially in other states and foreign countries. As a result, magnetic recordation of digital information on credit cards has increased enormously in recent years. Moreover, as the use of credit cards has proliferated, the use of magnetic stripes on the back of cards has been expanded to include other types of cards. For example, toll cards, membership cards, and pass cards for gaining admittance to homes, offices, garages and the like now commonly employ the technology of encoding information on a magnetic stripe on the back of the cards.
With the increased use of magnetic stripe encoded cards there has been a substantial increase in the demand for better devices which read such magnetically recorded information on the magnetic stripe. The demand is particularly high in the retail and banking establishments.
In order to effect a reading of the magnetic stripe on the card, the card must be moved through a device having a magnetic reader head, which engages the magnetic stripe on the back of the card. There two common types of such devices are "sweep" types and "insertion" types. The "sweep" type requires the user to "sweep" the edge of the card bearing the magnetic stripe thereon through a channel in which the magnetic head is positioned. The "insertion" type requires the user to push then pull the card into a slot, through which the card is read or encoded while pushing or pulling the card. The contact between the magnetic stripe and the magnetic head is of utmost importance in accurately reading the information on the magnetic stripe. Thus, it is essential to create and maintain smooth, constant engagement between the magnetic stripe and the magnetic head.
One of the primary problems with contemporary magnetic stripe reading devices is something referred to as "jitter." Jitter is the term used to describe the phenomenon that occurs when the magnetic head vibrates. Vibration primarily occurs when the card is initially inserted into the card reader slot, but can also occur while the card is being passed through the slot if the magnetic stripe is not maintained firmly against the magnetic head. Generally, ANSI standards allow for up to 10% bit to bit jitter as being an acceptable level from unused encoded cards. However, although not specified in any standard, the lowest possible percentage of bit to bit jitter added by reading devices used in the field will insure optimum efficiency exemplified by error free reading to the end user.
Another problem with contemporary magnetic stripe reading devices is that of mechanically coping with deformed or warped cards. In order to obtain an accurate reading of the magnetic stripe, it is necessary to maintain the magnetic stripe against the magnetic head of the reading device during the transport of the card through the card reader slot. When the card is not relatively flat it can be a difficult task to keep the magnetic head in contact with the magnetic stripe.
The conventional approach to coping with deformed or warped cards has been to provide spring loaded magnetic heads in which the spring urges the magnetic head against the magnetic stripe. Although this approach has been successful to some extent, it does not address the problem ofjitter. In fact, designs which utilize spring loaded magnetic heads, the spring can actually increase the problem with jitter. The flexible nature of the spring permits the magnetic head to vibrate initially upon card entry to the extent that reader induced bit to bit jitter above 10% is common. Jitter readings are frequently inconsistent in spring designs. Furthermore, the use of a spring loaded magnetic head can create the additional problem of unevenly wearing the magnetic stripe on the back of the card. Spring devices align the read head to the form of the card or ticket as it is inserted. During alignment, forces are exerted where the head initially contacts the magnetic stripe which can damage the media at point of contact. This invention eliminates spring alignment induced damage by forming the card into a flattened form, as it is brought into contact with the magnetic head, which causes the magnetic stripe to properly engage the magnetic head without damaging the media.
In U. S. Pat. No. 4,254,441 to Fisher, a digital code reader is provided which has a fixed magnetic head. The fixed magnetic head is provided with the objectives of increasing both the reliability and the life span of the device compared to devices which utilize a spring biased magnetic heads. In FIG. 7 of Fisher, the pathway through which the card travels and the position of the magnetic head reveal the potential for a significant amount of jitter. When a card is inserted through the entrance passage, i.e. from the left hand side of the device, it can be seen that the leading edge of the card is almost certain to strike the magnetic head. This contact between the edge of the card and the magnetic head is very likely to cause substantial vibrations resulting in jitter.
Therefore, there is a need for a magnetic stripe reading device that alleviates problems with contemporary devices, provides for improved contact between the magnetic stripe and the magnetic head, and also satisfies the need to reduce the jitter.